Pixel-Level Detection of Each Object of the Same Class In an Image
What you want to do is instance segmentation on a pixel level.
I can point you two different way:


MaskRCNN, which in a nutshell, uses Region Proposal Networks then segment in the proposed regions.
Some other works which don't use Region Proposals rather, regress the pixels of the image in an embeding space to be able to apply some clustering algorithm. Here is a link to a good blog post about it: https://towardsdatascience.com/instance-embedding-instance-segmentation-without-proposals-31946a7c53e1